i posted a similar question a few days ago but I want to try it this way again.
I'm trying to delineate catchments for an urban watershed whichs drainage consists mainly of open-channel flow. The open channels are connected to a larger number of lakes.
My current problem is that most of the lakes and drains are not represented in the DEM. The general elevation in my catchment is low and doesn't vary much (2-6 m.a.s.l), some parts are even below sea level. When I use DEM reconditioning I get negative elevation values for larger parts of my drainage. If I apply Fill Sinks my burnt streams are filled up again & the resulting watersheds and drainage lines don't match what I want to see.
As my streams run through a couple of lakes I want to represent them also in the DEM. How would I do that?
When I use Create Sink Structure I just identify them as a polygon but I dont burn them into the dem, right?
I found the workflow for Combined dendritic/deranged terrain with known sink and stream locations
(yellow.esri.com - /archydro/archydro/) which might work in my case also, but I don't know how to overcome the issue that fill sinks always sort of recreates my initial dem with just slight changes. Most of my burnt streams are not recognizable anymore. If I use Fill Sinks with a threshold instead of Fill All I dont get the general eight flow direction (d8) output, but number from 1-255.
I have been searching through many Q&A, discussions and videos, but I couldnt find any detailed description or procedure of how to overcome this issue. I'd highly appreciate hints on representing the drains and lakes properly in the DEM & adjusting the flow direction.